﻿using System;
using System.Security.Cryptography;
using System.IO;
using System.Text;
using System.Collections.Generic;
using System.Web;
using System.Data;

namespace Card.Security
{
    /// <summary>
    /// 此类用来加密与解密存在于URL中的参数
    /// </summary>
    public class Utility
    {
        public Utility()
        {
        }
        private static string _StringKey = "plki;'sv"; //参数加密Key,长度为8位
        private static string _PassWordKey = "oplkjy.x";　//PassWord加密Key,长度为8位

        #region 公共方法
        /// <summary>
        /// 加密URL传输的字符串
        /// </summary>
        /// <param name="QueryString"></param>
        /// <returns></returns>
        public static string EncryptString(string str)
        {
            return Encrypt(str, _StringKey);
        }


        /// <summary>
        /// 解密URL传输的字符串
        /// </summary>
        /// <param name="QueryString"></param>
        /// <returns></returns>
        public static string DecryptString(string str)
        {
            return Decrypt(str, _StringKey);
        }


        /// <summary>
        /// 加密帐号口令
        /// </summary>
        /// <param name="PassWord"></param>
        /// <returns></returns>
        public static string EncryptPassWord(string PassWord)
        {
            return Encrypt(PassWord, _PassWordKey);
        }


        /// <summary>
        /// 解密帐号口令
        /// </summary>
        /// <param name="PassWord"></param>
        /// <returns></returns>
        public static string DecryptPassWord(string PassWord)
        {
            return Decrypt(PassWord, _PassWordKey);
        }
        #endregion

        #region 加密过程
        /// <summary>
        /// DEC 加密过程
        /// </summary>
        /// <param name="pToEncrypt"></param>
        /// <param name="sKey"></param>
        /// <returns></returns>
        private static string Encrypt(string pToEncrypt, string sKey)
        {
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();　////把字符串放到byte数组中

            byte[] inputByteArray = Encoding.Default.GetBytes(pToEncrypt);

            des.Key = ASCIIEncoding.ASCII.GetBytes(sKey);　////建立加密对象的密钥和偏移量
            des.IV = ASCIIEncoding.ASCII.GetBytes(sKey);　 //原文使用ASCIIEncoding.ASCII方法的GetBytes方法
            MemoryStream ms = new MemoryStream();　　 //使得输入密码必须输入英文文本
            CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(), CryptoStreamMode.Write);

            cs.Write(inputByteArray, 0, inputByteArray.Length);
            cs.FlushFinalBlock();

            StringBuilder ret = new StringBuilder();
            foreach (byte b in ms.ToArray())
            {
                ret.AppendFormat("{0:X2}", b);
            }
            ret.ToString();
            return ret.ToString();
        }
        #endregion

        #region 解密过程
        /// <summary>
        ///  DEC 解密过程
        /// </summary>
        /// <param name="pToDecrypt"></param>
        /// <param name="sKey"></param>
        /// <returns></returns>
        private static string Decrypt(string pToDecrypt, string sKey)
        {
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();

            byte[] inputByteArray = new byte[pToDecrypt.Length / 2];
            for (int x = 0; x < pToDecrypt.Length / 2; x++)
            {
                int i = (Convert.ToInt32(pToDecrypt.Substring(x * 2, 2), 16));
                inputByteArray[x] = (byte)i;
            }

            des.Key = ASCIIEncoding.ASCII.GetBytes(sKey);　////建立加密对象的密钥和偏移量，此值重要，不能修改
            des.IV = ASCIIEncoding.ASCII.GetBytes(sKey);
            MemoryStream ms = new MemoryStream();
            CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write);

            cs.Write(inputByteArray, 0, inputByteArray.Length);
            cs.FlushFinalBlock();

            StringBuilder ret = new StringBuilder();　////建立StringBuilder对象，CreateDecrypt使用的是流对象，必须把解密后的文本变成流对象

            return System.Text.Encoding.Default.GetString(ms.ToArray());
        }
        #endregion

        #region 匹配过程
        /// <summary>
        /// 检查己加密的字符串是否与原文相同
        /// </summary>
        /// <param name="EnString"></param>
        /// <param name="FoString"></param>
        /// <param name="Mode"></param>
        /// <returns></returns>
        private static bool ValidateString(string EnString, string FoString, int Mode)
        {
            switch (Mode)
            {
                default:
                case 1:
                    if (Decrypt(EnString, _StringKey) == FoString.ToString())
                    {
                        return true;
                    }
                    else
                    {
                        return false;
                    }
                case 2:
                    if (Decrypt(EnString, _PassWordKey) == FoString.ToString())
                    {
                        return true;
                    }
                    else
                    {
                        return false;
                    }
            }
        }

        public static bool ValidatePassword(string encodePassword, string password)
        {
            return ValidateString(encodePassword, password, 2);
        }
        #endregion

    }
}
